Short-Wave Infrared Chip-Spectrometer by Using Laser Direct-Writing Grayscale Lithography

摘要

Short-wave infrared (SWIR) information is critical for material analysis,imaging sensing, and other fields. To acquire SWIR spectrum with compactdevices, strategies for reconstructive microspectrometer have emerged, suchas photonic crystal and quantum dot filter. However, the current SWIR microspectrometerneeds many filters with insufficient resolution. In this work, theauthors develop a SWIR chip-spectrometer based on Fabry–Perot microcavitiesarray which can be fabricated by using fast and low-cost UV laser directwritinggrayscale lithography. The ultra-compact chip-spectrometer can workin a very wide range from 900 to 1700 nm with only 20 detector pixels and areconstruction algorithm. The spectral resolution achieves 2 nm by 50 pixelsset and 5 nm by 20 pixels set at SWIR range, which is 3 times higher, with3.9 times less units number, than for recently reported SWIR quantumdot spectrometers. To the best of our knowledge, this is a minimum highresolutionSWIR InGaAs detector based chip-spectrometer which can work inthe whole SWIR band with only 20 detector pixels. It has great potential forapplications in smart-phone or other miniature portable spectrometers.